Am I right in assuming a dying starter?

[Invertigo]

Car getting slower to crank over the last few weeks. Petrol engine (BMW M54). Happens both hot and cold.

Battery voltages are healthy both when everything is off (12.6-7) and when engine on (14.5) so it seems that's fine.

So my next consideration is a worn out starter? It's a factory part, so 15 years and 115k miles under its belt now.

Sensible? Or am I missing something?

[E-bmw]

Check (I mean proper check, not look at & say it is connected) all electrical connections at starter alternator & battery first.

Many "starter" issues are just a slightly corroded/loose connection.

[Invertigo]

Makes sense, but arguably a loose connection would have some sort of impact on the battery charging too? As the starter is situated in between the alternator and the battery on the positive circuit (battery is in the boot).

Either way I reckon I'll pick up a starter from the local motor factors anyhow and drop it back if it turns out to be a bad connection. I was more considering if there's anything else a possibly other than battery/connections/starter itself

[paintman]

E-bmw said:

Check (I mean proper check, not look at & say it is connected) all electrical connections at starter alternator & battery first.

Many "starter" issues are just a slightly corroded/loose connection.

^^^^This.
The battery needs checking to be sure it's holding charge. Your reading with engine off may well be surface charge & your reading when running just suggests your alternator is OK.
Fully charge the battery with a battery charger & see what happens.
Can be worth connecting a jump lead directly form the battery earth terminal to a good clean point on the block to see if it makes any difference.

[Penelope Stopit]

As above, there is only one sure way of checking a battery and that is carrying out a load test on it after charging it and leaving it standing to cool for several hours

[GreenV8S]

Invertigo said:

am I missing something?

You haven't proved anything. To know whether the starter is faulty you'd need to measure the voltage across the starter while it was loaded, and compare that to the voltage across the battery. Depending on the type of failure, you might also need to measure the current draw.

[Invertigo]

Well, as I work right near Eurocarparts I figured I'd pop in and collect a starter and battery just in case.

Went to start the car after work and it was nearly dead. Swapped battery over and no change. Took 5 attempts at cranking to get it running, was worried I'd have to try and get the security guys to bump start me.

Anyway, tried starting again at home and totally dead, not a sound from the motor but all electrics working perfectly. Changed over the starter, jumps to life immediately upon turning the key now.

It would have been prudent to get the battery load tested for sure, but frankly I'm glad I picked up the parts or I'd be stuck without a car tomorrow.

So, tl;dr it was a bad starter, replaced and all is good again

[E-bmw]

Invertigo said:

So, tl;dr it was a bad starter, replaced and all is good again

If I am reading what you said correctly, you haven't proved that at all.

You changed battery & starter, it didn't work, you changed battery back it still didn't work, you changed starter back & it worked.

So that says you are now back where you started & it works, so basically you have removed & refitted a few connections & it now works.

[milkround]

E-bmw said:

If I am reading what you said correctly, you haven't proved that at all.

You changed battery & starter, it didn't work, you changed battery back it still didn't work, you changed starter back & it worked.

So that says you are now back where you started & it works, so basically you have removed & refitted a few connections & it now works.

No he changed the starter only and now it's all good.

It still might not have been a totally dodgy starter - and I'd have been cleaning and checking electrical connections myself. The thing is he needed a vehicle to get to work so couldn't pull it off and take the starter apart, order random bushes from the web and wait so he did right by himself.

Hes got a result though. A fully working car and he didn't have to pay no one to fit anything for him. Done better than 95% of this website and the population who'd have called the AA and had a mechanic sort him out.

[Penelope Stopit]

milkround said:

E-bmw said:

If I am reading what you said correctly, you haven't proved that at all.

You changed battery & starter, it didn't work, you changed battery back it still didn't work, you changed starter back & it worked.

So that says you are now back where you started & it works, so basically you have removed & refitted a few connections & it now works.

No he changed the starter only and now it's all good.

It still might not have been a totally dodgy starter - and I'd have been cleaning and checking electrical connections myself. The thing is he needed a vehicle to get to work so couldn't pull it off and take the starter apart, order random bushes from the web and wait so he did right by himself.

Hes got a result though. A fully working car and he didn't have to pay no one to fit anything for him. Done better than 95% of this website and the population who'd have called the AA and had a mechanic sort him out.

I don't know what you two have been reading and I stand to be corrected

I read it as the new battery was fitted and made no difference, the new starter was then fitted and all is good
I didn't read anything about the new battery being removed

[E-bmw]

milkround said:

E-bmw said:

If I am reading what you said correctly, you haven't proved that at all.

You changed battery & starter, it didn't work, you changed battery back it still didn't work, you changed starter back & it worked.

So that says you are now back where you started & it works, so basically you have removed & refitted a few connections & it now works.

No he changed the starter only and now it's all good.

It still might not have been a totally dodgy starter - and I'd have been cleaning and checking electrical connections myself. The thing is he needed a vehicle to get to work so couldn't pull it off and take the starter apart, order random bushes from the web and wait so he did right by himself.

Hes got a result though. A fully working car and he didn't have to pay no one to fit anything for him. Done better than 95% of this website and the population who'd have called the AA and had a mechanic sort him out.

OK, I stand partially corrected, when you wrote about collecting starter & battery I assumed you fitted them, my bad, but still not confirmed the issue, could have been a simple fix as suggested, but at least you have it working.

[Invertigo]

No new battery boys, merely checked the voltages and all was well (as you might expect on a battery just over 2 years old). I did try hooking up a new one but it made no difference, so it was swapped back.

Also hooked the old starter directly up to the battery out of curiosity. It was spinning significantly slower than the new one, and that's without having the load of a reasonably large engine to crank.

It probably was just worn out brushes, but I need the car daily and didn't have time to strip down and rebuild, as much as I love tinkering with things. So a rebuilt replacement off the shelf went in.

Edited by Invertigo on Thursday 30th May 23:57

[GreenV8S]

Good result.

[milkround]

Invertigo said:

No new battery boys, merely checked the voltages and all was well (as you might expect on a battery just over 2 years old). I did try hooking up a new one but it made no difference, so it was swapped back.

Also hooked the old starter directly up to the battery out of curiosity. It was spinning significantly slower than the new one, and that's without having the load of a reasonably large engine to crank.

It probably was just worn out brushes, but I need the car daily and didn't have time to strip down and rebuild, as much as I love tinkering with things. So a rebuilt replacement off the shelf went in.

Edited by Invertigo on Thursday 30th May 23:57

As someone who is currently waiting on parts to rebuild his brake caliper I can say you are making the right move.

I'm saving 40 quid by rebuilding it myself. And probably losing 2/300 in wages.

And part of the reason I need to rebuild the calipers is because I melted the rubbers when I had to use heat to get the caliper bolts off! My only saving grace is that the other side was massively stuck and I need the other bits to fix that.